Automatic transmission control



Jan. 25, 1938. H. A. SMITH AUTOMATIC TRANSMISSION CONTROL 3 Sheets-Sheet 1 Filed April 8, 1956 IIHH H 1| H II HI H il H WIN I N V EN TOR.

HARVEY A. SMITH A TTORN E Y Jan. 25, 1938. H. A. SMITH AUTOMATIC TRANSMISSION CONTROL 3 Sheets-Sheet 2 FIG].

Filed April 8, 1936 FlG.6-.

INVENTOR HARVEY A.SMITH.

ATT

Patented Jan. 25, 1938 UNITED STATES PATENT OFFICE AUTOMATIC TRANSMSSION CONTROL Harvey A. Smith, Webster Groves, Mo.

Application April 8, 1936, Serial No. 73,200

Claims.

My invention relates to the automatic control of power transmission from a driving to a driven member and particularly'to that type of transmission in which the relative speed of rotation between the driving and driven members is determined by fluid pressure means. While my invention is primarily adapted to the transmission of power from the motor to the wheels of a motor vehicle, it may be adapted to various other types of power transmission.

One object of my invention is to provide mean for controlling the admission and discharge of fluid to and from the fluid pressure means by a torque-actuated device so that the speed ratio is automatically regulated in a selective and flexible manner to adapt it to the load tobe driven.

Another object of my invention is to provide manually-operated means independent of the torque-actuated device for controlling flow of fluid to and from the fluid pressure means.

A further object of my invention is to provide manually-operated means cooperating with the torque-actuated means for controlling the action of the fluid pressure means.

In the accompanying drawings, which illustrate two forms of transmission mechanism made in accordance with my invention, Figure 1 is a vertical longitudinal section of one form of my invention adapted for use as an automobile transmission; Figure 2 is a section taken on the line 2-2 of Figure 1; Figure 3 is a section taken on the l ne 3-3 of Figure 1; Figure 4is a section taken on the line 4-4 of Figure 1; Figure 5 is an enlarged section taken on the line 55 of Figure 2; Figure 6 is a section taken on the line 66 of Figure 1; Figure 7 is a detail View of one of the torque discs; Figure 8 is a rear view of the driving spider; Figure 9 is an enlarged view showing a modification of the torque disc; Figure 10 is an enlarged side view of a portion of the torque discs; Figure 11 is an enlarged longitudinal sec- I tion of one of the retarding cylinders; Figure 12 is an enlarged cross section through the cylinder; Figure 13 is a side view, partly in section and partly in elevation, showing a modification; Figure 14 is a semi-section taken on the line I4-I4 of Figure 13; and Figure 15 is a section taken on the line I5-I5 of Figure 13.

Referring first to Figures 1 to 12, inclusive.

showing a form of my device particularly adapted for use as an automobile transmission, the numeral I indicates the fly-wheel of the motor to which is secured by bolts 2, a spider forming the driving member and comprising an annular part 3 and a disc-shaped plate 4 connected by a web 5.

Projecting inwardly from the part 3 are three lugs 6 (Figures 1 and 8). In these lugs and the plate 4 are journaled short shafts 'I each carrying a planet gear 8. On the inner end of each shaft is a crank-arm 9 connected by a pitman II] to piston II of one of three cylinders I2 secured to. the face of the plate 4 by any suitable means, such as bolts I3.

Each cylinder is provided with a valve casing I4 communicating with the cylinder through a port I5 (Figures 11 and 12). One end of the casing is closed by a plug l5 provided with a seat for a main valve I6 and the other by a plug I! having a seat for an auxiliary valve l8. These valves are preferably of the ball type and are held against their seats by a coil spring I9 positioned between them. Threaded in the plug I5 is a smaller plug having one or more prongs 2| en-t Each of the plugs 20 is provided with an arm 22 by means of which it may be operated by a torque-actuated device, hereinafter described, to regulate the flow of oil or other fluid through a port 23 in the plug. The plug I1 is provided with a central port 24 through which projects the L- shaped end of a rock-shaft 25 journaled in lugson the cylinder. Brazed or otherwise secured to each rock-shaft is a plate 26 having a tail piece 21 connected by a tension spring'28 with the plate 4, which spring holds the L-shapedend of the rock-shaft against the valve I8 to unseat it and permit free passage of fluid through port 24. When, however, plate 26 is moved toward the cylinder the L-shaped end is retracted, permitting the seating of the valve under tension of spring I9.

Centrally carried on plate 4 is a sleeve 30 in which freely rotates a shaft 3| constituting one part of the driven element of the device. On the end of the shaft 3| is a sun gear 32 meshing with the planet gears 8. Mounted on the sleeve 30 is a spider 33 having three arms 34 each connected to a slot 35 in one of the arms 22 on the valve controlling plugs 20 so that when the spider is moved longitudinally of the sleeve, the position of the ball valves I6 will be controlled. Longitudinal movement is imparted to the spider by a sleeve 36 connected thereto by a bearing 31, preferably of anti-friction type, so that these parts:

move together longitudinally but arefree to rotate independently. The driving member, to-

gether with its cylinders and the spider, are enclosed in a reservoir casing 38 held in position by bolts 33. This casing contains oil, not only to supply the cylinders but to lubricate the running parts contained therein. Surrounding an offset part 4!] of the reservoir casing is an annular member 4| carrying three rods 42 normally held in contact with plates 26 by springs 43 (Figure 5) to retract the L-shaped ends of rock-shafts 25 and allow the secondary valves l8 to seat. To withdraw rods 42 and thus open valves I8, a'yoke 44 engages the member 4|. This yoke is pro- Vided with trunnions 65 engaged by arms- 46 on of the machine.

Rigiclly secured to the shaft 3| adjacent the reservoir casing is a collar 58 of a casting 5| forming one member of a torque-actuated device. Formed in thismember adjacent the collar 56 are openings 52 through which project arms 53 formed by slotting the'e'ndlof sleeve 36. The ends of these arms are threaded to receive a cap 54-having trunnions 55 engaged by arms 56 carried on a rock-shaft 51.- This shaft is journaled in the member 5| and has a projecting end on which is carried a slotted arm58. A second member 59 of the torque-actuated device is'mounted on the shaft 3|. by means of a collar 68 soas to have rotary movement relative thereto and, consequently, to the first member of the device. The members 5| and .59 are provided with flanges 6| and 62, respectively, which are clamped together by bolts 63 surrounded by springs 66 to provide a friction cushioning effect upon the movement between the partsand this movement is limited by slots 65 in the flange 62, through which slots the bolts pass. Carried by the part 5| are a pair of brackets 66 and on the part 59 a pair of similar brackets 61. Each of the brackets is provided with a boss 68 to engage one end of ahelic-al spring 69, two of which are employed, each being interposed between one of the brackets 66 and one of the brackets 61.. The brackets on each part are alternately arranged, as best shown in Figures Gand 7, so that both'springs oppose relative movement of the parts in the same direction. When the springs 69 are compressed by the torque resultant from transmitting power from member 5| to 59, the two parts have relative rotary movement causing a pin 10 on the flange 62 and engaging the slotted arm 58 to move said arm from the position shown in full lines in Figure 10 to that shown in dotted lines. This actuates the rock-shaft 51 to move the sleeve 36 and spider 33 toward the left-hand end of Figure 1 and so open the primary cylinder valves 6.

If it is desired to adjust the tension of the springs 69, one end of each spring, instead of bearing directly on its bracket, engages with an adjustable boss H (Figure 9). This boss has a stem 72 threaded into the, bracket so that by rotating the boss in one direction or the other, the tension of the spring may be increasedor decreased.

Some means for throwing the machine into reverse or'neutralpositions is necessary. At the right-hand end-of Figure 1, I have shown an old and well-known form of such means comprising a gear 86 keyed to the collar 66 and meshing with a' gear 8| on a counter-shaft 82. The gear 8| is connected to a gear 83 meshing with a reversing gear 84. A shaft 85, forming a continuation of shaft 3| and extending to the differential of the machine, has splined on it a gear 86 provided with internal and external teeth. When gear 86 is in the position shown, the device is in neutral and the part 3| of the driven member is free to rotate without imparting motion to the part 85. When the gear 86 is moved to the left, its internal teeth engage with the teeth of gear 86, thus effecting direct coupling between shafts 3| and 85. When the gear is moved to the right, its external teeth engage with gear 84, thus reversing the direction of rotation of shaft 85 with respect to shaft 3| so that the car may be backed.

Briefly stated, the operation of my device is as follows: When the machine is started with the engine running, the clutch pedal is depressed to open the secondary valve l8. This permits the pistons to move freely in the cylinders so that 1 part 3| of the driven shaft comes to rest, after which gear 86 is moved into mesh with gear 88, by the clutch lever. The clutch pedal is now released to close valves l8. Upon closure of valves I8, the movement of the pistons in the cylinders is checked so that rotation of planet, gears 8 isprevented and the driving member is locked to shaft 3|. Movement of shaft 3| is now transmitted to the wheels of the car. As the power is transmitted through the torque-actuated device, the inertia of the car will cause springs 69 of the torque device to be compressed, thus opening the primary valves |6 to such a degree as to lower thespeed ratio between the driving and driven members until the resistance of the car to movement is overcome. As this result is being accomplished, the valves |6 will be gradually closed by the return of spring 69 to normal, which occurs under normal running conditions. If at any time the "resistance of the car is increased, as forexarn'ple, by moving up an incline, the springs 69 are again compressed to open the valves l6 to a greater or less degree, as required tosecure the necessary reduction of speed ratio between thedriving and driven members to compensate for the increased resistance.

In Figures 13 and 14 I have shown a modification of my device to adapt it to applications where it is desirable to regulate the output of a power unit in'amanner similar to that accomplished by a steam throttle or by a rheostat in the case of an electric motor. In this construction I supplement the torque-actuated control of the retarding cylinders by a manual control cooperating therewith so that the output is regulated by their combined action. A spider 87, corresponding to the driving member of the first des'cribed'construction, carries'the planet wheels 8 meshing with the sun wheel 32 on the driven shaft 88 towhich is directly keyed the member 5| of the torque-actuated device. The planet wheels drive the pistons of cylinders E2, which are like the cylinders 52 except that they are provided only with primary valves, the function of the auxiliary valves being unnecessary in this construction. The primary valves are actuated by racks 89 engaging with gears 96 on the valve plugs. It will be understood that this method of actuating the valves may 'be substituted for the slotted arms 22 in the form previously described. The racks are carried on a spider 33 similar to the spider 33. This spider is moved longitudinally by the engagement of its hub 9| by the ends of a spilt sleeve '32 connected tothe arms 56 of the rockshaft5l by a yoke 93 so as to permit relative rotary movement between the two partsof the torsion device without disturbing the connection.

To prevent disengagement of the racks 88 from the gears 90, the former are provided with U- shaped guards l3 embracing the gears, as best shown in Figure 15. The hub is held against the ends of the arms 92 by a coil spring 94 interposed between the hub and an abutment 95 which preferably provides a bearing for a sleeve 96. This sleeve is formed integral with the part 59 and constitutes the second part of the driven member connected either directly or indirectly to the load. The hub is provided with a yoke 91 having trunnions 98 engaging open-sided slots 99 in an arm I99 carried by a lever lfll mounted on a shaft or stud M32. The lever is provided with a dog I03 engaging with one or the other of a series of notches I99 in arcuate rack I05.

When the parts are in the position shown, with the hub 9| bearing against the ends of arms 92, the opening of the cylinder valves will depend solely upon the compression of the springs of the torque device. If, however, the dog 193 is moved up into engagement with one of the other notches I9 3, the hub will be moved out of contact with the arms 92 carrying with it the spider 33' and thus opening the cylinder valves to a greater or less degree, as desired. This determines the maximum ratio between the driving and driven members, which ratio cannot be exceeded while the manual control is in this position. Should the torque transmitted exceed that corresponding to this ratio, the arms 92 will contact the hub and move it further to the left, an operation permitted by the open-sided slots 99 out of which the trunnions may be moved. The speed ratio will now be under automatic control of the torque device.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a device of the class described, the combination with a driving member, of a driven member, sun and planet gearing connecting said members, a cylinder controlling said gearing and determining the relative speed of rotation of said members, a main valve for said cylinder, an auxiliary valve for said cylinder, torque-actuated means for controlling said main valve, and manually-actuated means for controlling the auxiliary valve.

2. In a device of the class described, the combination with a driving member, of a driven memher, a plurality of cylinders carried by one of said members, pistons carried by the other of said members, planet gears also carried by said members and driving said pistons, each of said cylinders being provided with a main valve and an auxiliary valve, a sun gear carried by the other :lember and engaging said planetary gears, torque-actuated means for controlling the main piston valves, and manually-actuated means for controlling the auxiliary piston valves.

3. In a device of the class described, the combination with a driving member, of a driven member, a plurality of cylinders carried by one of said members, pistons carried by the other of said member, planet gears also carried by one of said members and provided with crank means driving said pistons, each of said cylinders being provided with a valve, torque-actuated means including a pair of torque members having limited relative movement, one of said torque members being regidly connected to the driven member, spring means interposed between the torque members to oppose their relative movement, connections operated by the relative movement of the torque members, said connections controlling the cylinder valves, auxiliary valves for said cylinders, and manually-operated means for actuating said auxiliary valves.

4. In a device of the class described, the combination with a driving member provided with a sleeve, of a driven shaft extending through said sleeve, planet gears carried by said driving member, a sun gear carried by said shaft and meshing with said planetgears, cylinders mounted on the driving member, pistons in said cylinders, said pistons being crank driven from said planet gears, valves for said cylinders, a reservoir casing carried by the driving member and enclosing the cylinders, a collar on the sleeve projecting through the casing, connections between said collar and the cylinder valves for actuating the latter, a two part torque-actuated device positioned outside of the reservoir casing, one part of said torque device being connected to the driven shaft and the other to the sleeve, and means operative upon the relative movement of the parts of the torque device for shifting the collar to control the cylinder valves.

5. In a device of the class described, the combination with a driving member provided with a sleeve, of a driven shaft extending through said sleeve, planet gears carried by said driving member, a sun gear carried by said shaft andmeshing cylinder valves for actuating the latter, a two part torque-actuated device positioned outside of the reservoir casing, one part of said torque device being connected to the driven shaft and the other to the sleeve, means operative upon the relative movement of the parts of the torque device for shifting the collar to control the cylinder valves, auxiliary valves for the cylinders, and manuallyoperated means for actuating said auxiliary valves.

HARVEY A. SMITH. 

